KJet

K-Jetronic, also known as KE Jetronic or K-Jet, is an early continuous fuel-injection system developed by Bosch that was widely used on European cars from the 1970s through the 1980s. It belongs to the Jetronic family of fuel-injection systems and is characterized by a mechanical method of metering fuel in response to measured air flow rather than by electronic pulse control.

Operation centers on measuring the amount of air entering the engine with an air-flow sensor (such as a vane-type meter or venturi arrangement). The movement of the air meter drives a mechanical fuel distributor, which meters fuel and distributes it to the individual injectors. Fuel pressure is maintained by a pump and regulator, while a warm-up regulator and other valves help manage fuel delivery at cold starts and under varying engine conditions. In the basic KE Jetronic design, fueling is largely mechanical and does not rely on a modern electronic engine-control unit, though some later variants integrated electronic controls.

Applications and impact: KE Jetronic was used across many European makes, including Volkswagen, Audi, BMW, Mercedes-Benz, Volvo, and Porsche, in a wide range of models. It offered continuous fuel delivery with relatively simple hardware compared to fully electronic systems of the era, but it required careful maintenance and periodic recalibration. Common maintenance concerns include air leaks, faulty seals, clogged injectors, and issues with the fuel pressure or warm-up regulator, all of which can affect idle stability and performance.

Legacy: KE Jetronic represented a major step in automotive fuel-injection technology and informed the later development of more sophisticated electronic systems such as L-Jetronic and Motronic, which gradually supplanted mechanical-only control. Some enthusiasts continue to restore and tune K-Jetronic vehicles for historical accuracy and driving experience.